public static extern int gvRenderFilename(GraphvizContextSafeHandle graphVizContextPtr, GraphSafeHandle graphPtr, [MarshalAs(UnmanagedType.LPStr)] char[] imageFormat, [MarshalAs(UnmanagedType.LPStr)] char[] outputFilePath);
public static extern int gvFreeLayout(GraphvizContextSafeHandle graphVizContextPtr, GraphSafeHandle graphPtr);
public static extern int gvLayout(GraphvizContextSafeHandle graphVizContextPtr, GraphSafeHandle graphPtr, [MarshalAs(UnmanagedType.LPStr)] char[] layoutEngine);
public static extern IntPtr gvcBuildDate(GraphvizContextSafeHandle graphVizContextPtr);
public static extern IntPtr gvcVersion(GraphvizContextSafeHandle graphVizContextPtr);
public static extern int gvRenderData(GraphvizContextSafeHandle graphVizContextPtr, GraphSafeHandle graphPtr, [MarshalAs(UnmanagedType.LPStr)] char[] imageFormat, out IntPtr renderDataResultPtr, out uint renderDataLength);